Renowned for his groundbreaking research on ocean acidifcation, Caldeira's been in the news this month for publicly chidingSuperfreakonomics authors Steven D. Levitt and Stephen J. Dubner for misrepresenting his research on geo-engineering as a substitute for agressive mitigation strategies aimed at reducing greenhouse gas emissions. (In fact, while Caldeira knows a lot about weather manipulation--perhaps more than any other climate scientist working right now--he views it as a last resort, only to be employed once we are certain about its many risks.)

Atmospheric scientist Ken Caldeira first became known for his groundbreaking work on ocean acidification, a phrase originally coined as a headline for one of his papers. Of late, however, Caldeira's research has led him into the controversial area of geo-engineering — the large-scale, deliberate manipulation of the Earth's climate system.

Many scientists have shied away from the subject because they feel it is a wrongheaded and dangerous path to pursue. But Caldeira — who heads a research lab at the Carnegie Institution for Science's Department of Global Ecology at Stanford University — has not been so dismissive, in part because his climate modeling has demonstrated that some geo-engineering schemes may indeed help reduce the risk of climate change. In fact, few scientists have thought harder about the moral, political, and environmental implications of geo-engineering.

Caldeira has become a focal point recently in the controversy surrounding the publication of Steven D. Levitt and Stephen J. Dubner's SuperFreakonomics, the follow-up to their previous best-seller, Freakonomics. A chapter of the book that deals with geo-engineering and quoted Caldeira was circulated on the Internet prior to the book's publication and was widely criticized for its poor understanding of climate science and its cynical, contrarian perspective.